The joining of a shackle to a chain poses a problem that has proved difficult to solve satisfactorily. It is impossible to insert the body of a standard shackle into the end link of the chain unless a small shackle is used whose strength is clearly lower than that of the chain. If, conversely, a shackle pin is inserted into the end link of the chain, that pin may have a diameter substantially equal to that of the links of the chain. But a pin, being rectilinear, operates under less favorable conditions than a chain link and, in order to exhibit the same strength as a link, would have to have a diameter greater than that of the link. In both cases, the shackle is a weak point in the chain and prevents the chain from being used with loads which it could otherwise carry.